The C.L.E.A.R. System: Canadian Lead-time Early Air Response
Providing 6–48 Hours of Advance Warning for Wildfire Smoke
C.L.E.A.R. is a wildfire PM2.5 early warning system for Toronto, Edmonton, Montréal, and Vancouver that repurposes existing NAPS air quality stations located 100–600+ km away to provide 6–48+ hours of advance warning before dangerous smoke arrives.
"Can hourly PM2.5 readings at distant monitoring stations predict a city's PM2.5 levels with enough lead time to issue meaningful public health warnings?"
Develop an early warning system that uses existing NAPS and U.S. EPA monitoring infrastructure — stations located 100–600+ km upstream — to detect approaching wildfire smoke plumes and issue colour-coded health alerts 6–48 hours in advance.
The system targets four major Canadian cities: Toronto, Edmonton, Montréal, and Vancouver, covering diverse geographic and smoke exposure patterns.
National Air Pollution Surveillance Program
Hourly PM2.5 measurements. 84% of stations concentrated in BC, AB, ON, and QC. Dense regional coverage enables upstream smoke detection.
Air Quality System & AirNow
Daily PM2.5 data from U.S. border stations (NY, PA, VT, WA, OR). Critical for cities near the U.S. border.
The system was validated against all historical smoke events (2003–2023):
| City | True Pos. | False Neg. | True Neg. | False Pos. | Detection | False Alarm | Status |
|---|---|---|---|---|---|---|---|
| Vancouver | 14 | 0 | 10 | 0 | 100% | 0% | Perfect |
| Edmonton | 9 | 1 | 5 | 0 | 90% | 0% | 1 Failure |
| Toronto | 10 | 0 | 10 | 0 | 100% | 0% | Perfect |
| Montréal | 14 | 0 | 10 | 0 | 100% | 0% | Perfect |
| Total | 47 | 1 | 35 | 0 | 97.9% | 0% | 83 events |
Edmonton's single missed event was due to a NNW monitoring gap — smoke arrived from an unmonitored direction.
During the catastrophic Quebec wildfire event:
| Date | Station | Distance | PM2.5 | Threshold | Alert |
|---|---|---|---|---|---|
| June 3 | Parry Sound | 187 km NNW | 196 µg/m³ | >139.3 | EXTREME |
| June 6 | Cornwall | 387 km ENE | 160 µg/m³ | >99.3 | VERY HIGH |
| June 6 | Toronto | — | 97 µg/m³ | (Actual) | HIGH |
Analysis of the Canadian National Fire Database shows statistically significant increases in national burn area over the study period. The 2023 season burned over 18 million hectares, more than double any previous year.
Regression analyses were independently replicated across four AI platforms to ensure mathematical accuracy:
All four platforms produced mathematically equivalent results, which were then hand-verified against raw data.
The system uses a five-tier alert scale based on predicted PM2.5 concentrations:
| Alert Level | PM2.5 Level | Public Health Action Plan |
|---|---|---|
| LOW | < 20 µg/m³ | No precautions needed. |
| MODERATE | 21–60 µg/m³ | Sensitive groups (children/elderly) avoid strenuous activities. |
| HIGH | 61–80 µg/m³ | Everyone should reduce physical exertion. N95 or KN95 mask. Keep doors and windows closed. HVAC to recirculate. Run HEPA filter. |
| VERY HIGH | 81–120 µg/m³ | Avoid all outdoor activity. Keep hydrated. |
| EXTREME | > 120 µg/m³ | Halt indoor pollution. No frying or sauteing. No vacuuming. No candles. No wood-burning stoves. |
For each included station, the system uses a simple linear regression:
Alert thresholds at each station are computed by inverting the formula:
When a station's live PM2.5 reading exceeds its computed threshold, the corresponding alert is triggered — providing advance warning based on the station's distance and tier classification.
First system to repurpose existing NAPS infrastructure specifically for wildfire smoke early warning across multiple Canadian cities.
97.9% detection rate (47/48 events) with 0% false alarms (35/35 non-events) across all four cities.
Colour-coded alerts with specific health recommendations give the public clear guidance hours before smoke arrives.
The methodology can be extended to any city with nearby upstream monitoring stations.
Have suggestions, found a bug, or want to share how you're using C.L.E.A.R.? We'd love to hear from you.
ryanzander99@gmail.com